Chemistry review sheet
Final Review Sheet Radio Active Decays Alpha decay occurs when the nucleus emits an alpha particle. Alpha particles have a positive charge and are equivalent in size to a helium nucleus, and so they are symbolized as . Alpha particles are the largest radioactive particle emitted. This type of radioactivity results in a decrease in the atomic number by 2 and a decrease in the atomic mass by 4. The equation below shows uranium-234 undergoing alpha decay: